The most popular thing in red dot sights these days is the proliferation of enclosed emitter designs. Yes, they tend to be boxier, but they have a significant advantage. Their enclosed design means no rain, snow, dirt or other gunk can get between the emitter and the front lens to scramble your dot and make it useless. I’ve had exactly that happen to me during a rainy training session and, well, you’re pretty much screwed until you get something in there to clean it out.
I’ve tested a few enclosed emitter designs, from large, mailbox-sized affairs to smaller units that are great for everyday carry. Meprolight makes two enclosed red dots; the slightly larger RMR footprint Meprolight MPO Pro-F and the sight I’ve been using the more compact MPO Pro-S with its RMSc mount.
Like a lot of enclosed emitter reflex sight designs, there isn’t much room for mounting screws. The enclosed housing takes up too much room for that. To mount the sight, they use a dovetailed mounting plate (much like a small inverted ARCA-Swiss plate) onto which the sight itself is clamped. It’s simple and secure, but it adds more height to the sight making it more difficult or impossible to co-witness with iron sights depending on the gun you’re using.
The MPO Pro-S controls are simple and intuitive. The rubber up and down arrows on the left side are used to turn the sight on or off, to switch between automatic brightness adjustment and manual, toggle the brightness level up or down and to select the sight you want to use (dot, circle or both).
That little window in front is a light sensor for automatic brightness adjustment. You can choose to use that function or — like me — not. While I’m generally not a fan of auto brightness adjustment, the MPO Pro-S does a good job of distinguishing between where you’re aiming and where you’re standing. In other words, if you’re in a dark or shaded area and aiming at something in brighter light, the MPO Pro-S’s sensor distinguishes that well in most situations.
Windage and elevation adjustments are made with a small flat blade screw head. That’s a very good thing. You won’t have to have a tiny Allen or Torx wrench to adjust your sight. You can do it with the point of your knife blade or the edge of a casing.
The MPO Pro-S is hair over one inch wide. That means it mounts nicely on compact and full-size pistols. The photo above shows it on my 1.35-inch wide FN 509 Midsize Tactical. I also popped it onto my Springfield Hellcat to see what’s what. I can report that the MPO Pro-S plate and housing stick out slightly, but not so much that it’s an issue. Carrying the smaller 1-inch wide gun with the Meprolight mounted wouldn’t be a problem at all.
As you can see above, the Meprolight MPO Pro-S sits a little higher than a reflex sight that bolts on directly to the slide. That’s down to its mounting plate. On a gun like the 509 Midsize Tactical with its suppressor-height sights, that’s not a problem.
You can co-witness with suppressor-height sights. With standard sights…not so much.
I’m still able to co-witness despite the increased mounting height. On a pistol with standard irons, though, that’s probably not an option.
The MPO Pro-S gives you the option of a 3 MOA dot, a 33 MOA circle, or both at the same time. Edge-to-edge clarity is excellent and the reticles — whether you’re using the dot, the circle, or both — are clear and flare-free.
The MPO Pro-S has a lot in its favor. There’s the increasingly industry standard RMSc footprint. Logical, intuitive controls. Easy windage and elevation adjustments. Side-loading battery so you don’t have to dismount the sight when it’s time for a change. Optical excellence and three reticle choices. And the MPO Pro-S is priced reasonably, too. Literally the only downside is the added mounting height due to the plate. But for most users, that will never come into play and shouldn’t keep them from giving the Meprolight a good look.
– Dan Zimmerman, Shooting News Weekly
